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1982 Johnson 35Hp charging problem

C

C3HS

New member
Hello, this motor (J35ELCND) appears to not be charging the battery. With a fully charged battery it runs fine , but soon starts running very rough. I then have to charge the battery and the same problem occurs again. I have heard that a bad rectifier would cause this problem. Is there a typical problem with this motor that would prevent it from charging the battery?
 
Do some more testing.-------The battery is used to crank it over to start.---------Then the ignition is powered by the magneto.--------Many of these motors run without a battery as manual start models.
 
The terminology "soon" doesn't define a time period. How long does the engine run as it should before this problem takes place?

I've never heard of a rectifier causing a problem like that... however, test it as below and replace if it's faulty.

(Small Rectifier Description & Location)
(J. Reeves)

On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.

Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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Thank you for the replies. The motor initially starts and runs fine, at all power settings, then about 5 to 10 minutes later, it starts running running rough, with reduced power. The rough running seems to get worse over the next 5 minutes or so, and then the motor quits altogether. Then when I try to start the motor again, the battery won't turn the motor over until I recharge it. After recharging the battery, the motor will turn over and start, and run fine, but then the above problem repeats itself.
 
C3HS said:
Thank you for the replies. The motor initially starts and runs fine, at all power settings, then about 5 to 10 minutes later, it starts running running rough, with reduced power. The rough running seems to get worse over the next 5 minutes or so, and then the motor quits altogether. Then when I try to start the motor again, the battery won't turn the motor over until I recharge it. After recharging the battery, the motor will turn over and start, and run fine, but then the above problem repeats itself.
Click to expand...

That sounds to me like the engine is overheating and seizes up solid so that it will not crank over until it cools off, however you have said nothing about it becoming HOT.

When this problem pops it ugly head up... can you immediately turn that flywheel over by hand or is it locked up solid?
 
The overheat buzzer/alarm has gone off in the past, but the motor never seemed to freeze up. I think it may have been clogged at the water inlet. When the overheat alarm went off, I would shut the motor off, and then try to restart it and it started up with no problem.

I first noticed the rough running issue after finding water inside the motor area which was coming from a leak in the flexible hose that carries the hot water over to the water outlet connection. I have since replaced that hose and it does not leak, and I cleaned out the inside of the motor area.

I am reminded that at one point, while the engine was running really rough, I pulled one of the spark plug wires off and it had no effect on the rough running engine. But after replacing the water line and cleaning up the inside of the motor area, it would run good for a while and then run rough, but I did not try removing the spark plug wire again.
 
Do a cylinder drop test,using plastic pliers pull 1 wire at a time,listen for rpm drop. When issue recurs again do a spark test on all cylinders, A lightning blue snap with spark tester. Try a compression test on all cylinders to eliminate head gasket problem. Heat on electronics is fatal,coils could be breaking down causing loss of spark at cylinders, check coils with dvm after running motor
 
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Thanks. I will be 'reunited' with that motor in two weeks and will put the comments received to work. I am starting to think there are a couple of problems going on with this motor. Has anyone ever heard of this electric start Johnson 35 HP somehow discharging the battery while running and then quitting once the battery dies? I know that does not seem to make sense since the spark comes from the magneto and not the battery, but it sure seemed like this was also happening.
 
C3HS said:
Thanks. I will be 'reunited' with that motor in two weeks and will put the comments received to work. I am starting to think there are a couple of problems going on with this motor. Has anyone ever heard of this electric start Johnson 35 HP somehow discharging the battery while running and then quitting once the battery dies? I know that does not seem to make sense since the spark comes from the magneto and not the battery, but it sure seemed like this was also happening.
Click to expand...

I've had customers batteries go dead when the engine's running (or not running) due to a short of some kind resulting in a battery drain... BUT... to have a dead battery cause the engine to die?.... no, I've never encountered that.
 
Hello, I just wanted to let folks know that I did get that motor running. There were several problems. The engine was overheating and I found that the water pump was missing two of the five vanes causing the overheat problem. I replaced the water-pump vane piece. I was able to find one of the two broken vanes and got it out. I am not sure what happened to the other one, but the engine is not overheating anymore and is pumping cooling water out just fine. Also, the power-pack was cracked, maybe due in part to the overheat problem, and when the motor ran for a bit, it got hot and the power-pack stopped sending voltage to one of the coils. I had first switched the two coils, and saw that the problem stayed with the same cylinder so I did not replace either coil. When I replaced it, the engine ran fine. The were some other problems encountered as well. I needed to replace the rubber tube that carried water around to the weep hole. It had been spraying water inside the engine area and was causing the insulation on the wires to fail, and so I repaired those wires. Lastly, I found that the circular rubber gasket between the fuel input line and the engine was failing and leaking fuel, so I replaced that. So, it runs now. Thank you all for your help with this.
 
Better go out and buy some lottery tickets before your luck changes. By all rights, that motor should be scrap from repeated overheating. You got very lucky.
 
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